Most often, in science and medicine, they are talking numbers when they use the term 'significant". Meaning, enough numbers add up to be considered. The easy way to explain, when they tell you about risks of taking a pill or having a surgery, they only list 'significant' issues, those that were reported most often. They don't talk about the small numbers of other reactions, as not significant. So, if a theory has enough numbers adding up behind it, with information, studies, facts... And they are not small, but enough to warrant further examination and to be considered before non significant theories.... Significant is used. In other words "theoretical significant's" should mean... There is more than enough back up of information on that theory, to be taken seriously.